A recharge oscillator model for interannual variavility in Venus'clouds
A recharge oscillator model for interannual variavility in Venus'clouds
复制标题
金星云层年际变率的补给振荡模型
DOI：
10.1029/2020je006568
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Y. J. Lee
中科院分区：
文献类型：
--
作者：
Kopparla;P.;A. Seshadri;T. Imamura;Y. J. Lee
二氧化硫是金星大气中一种重要的辐射和化学痕量气体，其在云顶的丰度在年际到十年的时间尺度上变化。这种变化被认为是来自于将二氧化硫输送到云顶的对流强度的变化，尽管这种对流变化背后的动力学尚不清楚。在这里，我们提出了一个新的概念模型对流变化，连接云底水丰度的辐射效应云内的对流强度，这反过来又影响了云内的水传输。该模型由两个耦合方程组成，它们被识别为充放电振荡器。耦合方程的解是对流强度和云底水丰度在3-9年时间尺度上的有限振幅持续振荡。特征振荡时间尺度由对流云底部附近的辐射冷却时间和涡动混合时间的几何平均值给出。
Sulfur dioxide is a radiatively and chemically important trace gas in the atmosphere of Venus and its abundance at the cloud tops has been observed to vary on interannual to decadal timescales. This variability is thought to come from changes in the strength of convection which transports sulfur dioxide to the cloud tops, although the dynamics behind such convective variability are unknown. Here, we propose a new conceptual model for convective variability that links the radiative effects of water abundance at the cloud‐base to convective strength within the clouds, which in turn affects water transport within the cloud. The model consists of two coupled equations which are identified as a recharge‐discharge oscillator. The solutions of the coupled equations are finite amplitude sustained oscillations in convective strength and cloud‐base water abundance on 3–9 years timescales. The characteristic oscillation timescale is given by the geometric mean of the radiative cooling time and the eddy mixing time near the base of the convective clouds.